Wrapping a bale after it has been formed must be done to prevent the degradation of the crops rolled in the bale. For this reason, it is important to provide wrapping which extends about the entire circumference of the bale. It is also important to insure that the integrity of the wrapped bale is maintained over the entire circumference of the bale. Improperly wrapped bales, or bales with damaged wrapping or netting, result in damaged or rotting crops.
DE-A1-100 11 158 discloses a baler with a device for wrapping a bale with a wrapping sheet. The wrapping sheet is pulled off a supply reel by means of an advancing roller. The device has a sensor system which detects incorrect feeding of the wrapping sheet. The sensor system may be an optical sensor which detects the difference in light density between an area where the wrapping sheet is present and where it is not. If the sensor system detects a malfunction, the wrapping process is suspended. This sensor system merely detects whether the wrapping sheet has been properly deployed. It does not sense whether the wrapping sheet is damaged or whether the bale is properly wrapped.
U.S. Pat. No. 6,966,162 discloses a device for wrapping a bale with a wrapping sheet. The device has one or more sensors that detect whether the wrapping sheet has been properly deployed on the bale. A baling press is equipped with a wrapping device as well as a control or regulating unit that receives a signal from one or more sensors and acts to interrupt the wrapping of a bale in the event the signal indicates that the wrapping sheet has not properly advanced. The sensors can be optical sensors, mechanical sensors, distance sensors, infrared sensors or any other suitable type of sensor. These sensors may respond to changes in color or contrast. The sensors merely detect whether the wrapping sheet has been properly deployed. The sensors do not sense whether the wrapping sheet is damaged or whether the bale is properly wrapped.
In both of these prior art devices, if the wrapping sheet is not properly dispensed or if the wrapping sheet becomes jammed, the sensors are helpful to determine that a malfunction has occurred. In response, the wrapping process is suspended and an appropriate signal is sent. However, these sensors do not facilitate an understanding of whether the wrapping sheet or netting has been damaged or whether the bale was properly wrapped. It would, therefore, be beneficial to incorporate a sensor which could be easily incorporated into existing designs of balers and which would provide a signal if the bale was not properly wrapped.